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<H1 class="no-header">form_fieldtype 3x</H1>
<PRE>
<STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>                                          <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>form_fieldtype</STRONG> - define validation-field types


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>

       <STRONG>FIELDTYPE</STRONG> <STRONG>*new_fieldtype(</STRONG>
           <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>field</EM><STRONG>_</STRONG><EM>check</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
           <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>char</EM><STRONG>_</STRONG><EM>check</EM><STRONG>)(int,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*));</STRONG>
       <STRONG>int</STRONG> <STRONG>free_fieldtype(FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>set_fieldtype_arg(</STRONG>
           <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>,</STRONG>
           <STRONG>void</STRONG> <STRONG>*(*</STRONG> <STRONG>const</STRONG> <EM>make</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(va_list</STRONG> <STRONG>*),</STRONG>
           <STRONG>void</STRONG> <STRONG>*(*</STRONG> <STRONG>const</STRONG> <EM>copy</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
           <STRONG>void</STRONG>  <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>free</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(void</STRONG> <STRONG>*));</STRONG>
       <STRONG>int</STRONG> <STRONG>set_fieldtype_choice(</STRONG>
           <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>,</STRONG>
           <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>next</EM><STRONG>_</STRONG><EM>choice</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
           <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>prev</EM><STRONG>_</STRONG><EM>choice</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*));</STRONG>

       <STRONG>FIELDTYPE</STRONG> <STRONG>*link_fieldtype(FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>type1</EM><STRONG>,</STRONG>
                                 <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>type2</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>

</PRE><H3><a name="h3-new_fieldtype">new_fieldtype</a></H3><PRE>
       The  function  <STRONG>new_fieldtype</STRONG>  creates  a new field type usable for data
       validation.  Its parameters are function pointers:

       <EM>field</EM><STRONG>_</STRONG><EM>check</EM>
            This function checks  the  validity  of  an  entered  data  string
            whenever  the  user  attempts  to  leave  a  field.   It  has  two
            arguments:

            <STRONG>o</STRONG>   The  (FIELD  *)  argument  is  passed  in  so  the  validation
                predicate   can  see  the  field's  buffer,  sizes  and  other
                attributes.

            <STRONG>o</STRONG>   The second argument  is  an  argument-block  structure,  about
                which more below.

       <EM>char</EM><STRONG>_</STRONG><EM>check</EM>
            This function validates input characters as they are entered.  The
            form library passes it the character to be checked and  a  pointer
            to an argument-block structure.


</PRE><H3><a name="h3-free_fieldtype">free_fieldtype</a></H3><PRE>
       The  <STRONG>free_fieldtype</STRONG>  function  frees  the  space  allocated for a given
       validation type by <STRONG>new_fieldtype</STRONG>.


</PRE><H3><a name="h3-set_fieldtype_arg">set_fieldtype_arg</a></H3><PRE>
       The  function  <STRONG>set_fieldtype_arg</STRONG>  associates  three  storage-management
       functions with a field type:

       <EM>make</EM><STRONG>_</STRONG><EM>arg</EM>
            This  function  is  automatically applied to the list of arguments
            you give <STRONG>set_field_type</STRONG> when attaching validation to a field.   It
            stores  the  arguments in an allocated argument-block object which
            is used when validating input.

       <EM>copy</EM><STRONG>_</STRONG><EM>arg</EM>
            This function may be used by applications to copy argument-blocks.

       <EM>free</EM><STRONG>_</STRONG><EM>arg</EM>
            Frees an argument-block structure.

       You must supply the <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> function.  The other two are optional: you
       may  supply NULL for them.  In this case, the form library assumes that
       <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> does not allocate memory but simply loads the argument into  a
       single scalar value.


</PRE><H3><a name="h3-set_fieldtype_choice">set_fieldtype_choice</a></H3><PRE>
       The  form  driver  requests  <STRONG>REQ_NEXT_CHOICE</STRONG> and <STRONG>REQ_PREV_CHOICE</STRONG> assume
       that the possible values of a field form an ordered  set,  and  provide
       the forms user with a way to move through the set.

       The  <STRONG>set_fieldtype_choice</STRONG>  function  allows forms programmers to define
       successor  and  predecessor  functions  for  the  field  type.    These
       functions  take  the  field  pointer and an argument-block structure as
       arguments.


</PRE><H3><a name="h3-link_fieldtype">link_fieldtype</a></H3><PRE>
       The function <STRONG>link_fieldtype</STRONG> creates a new field type from the two given
       types.  They are connected by an logical 'OR'.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       The  pointer-valued  routines  return  NULL  on  error.  They set <STRONG>errno</STRONG>
       according to their success:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or out-of-range argument.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred, e.g., malloc failure.

       The integer-valued routines return one of the following codes on error:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or out-of-range argument.

       <STRONG>E_CONNECTED</STRONG>
            The field is already connected to a form.

       <STRONG>E_CURRENT</STRONG>
            The field is the current field.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred (see <STRONG>errno(3)</STRONG>).


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>, <STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       The  header  file  <STRONG>&lt;form.h&gt;</STRONG>  automatically  includes  the  header  file
       <STRONG>&lt;curses.h&gt;</STRONG>.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These  routines  emulate  the  System  V  forms library.  They were not
       supported on Version 7 or BSD versions.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.



                                                            <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>
</PRE>
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<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-new_fieldtype">new_fieldtype</a></li>
<li><a href="#h3-free_fieldtype">free_fieldtype</a></li>
<li><a href="#h3-set_fieldtype_arg">set_fieldtype_arg</a></li>
<li><a href="#h3-set_fieldtype_choice">set_fieldtype_choice</a></li>
<li><a href="#h3-link_fieldtype">link_fieldtype</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-AUTHORS">AUTHORS</a></li>
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